Fred, I agree with Paul. I have never heard of anyone else having a problem with a sprint booster causing a problem with a car. It could be a number of things, and it could just be cooinsidental that it happened at the same time as you installed the SB. Have you checked the battery? Are you showing an error code on the dash? If you provided some more information, we may be able to help you diagnose the problem and potentially save you some money.